We are investigating the properties of collagen solubilized with pepsin from normal human intervertebral discs. We are also studying, by CNBr degradation, the fraction of collagen which remains insoluble. Our purpose is to determine whether more than one type of collagen might be present in nucleus pulposus and in annulus fibrosus. Intervertebral disc proteoglycans (PG) are being purified and studied by density gradient centrifugation and agarose gel filtration to determine the composition and properties of fractions already isolated. We intend to apply the information obtained on collagen and PG of normal intervertebral disc to the study of autopsy and surgical specimens of intervertebral disc of patients with "idiopathic" and other forms of scoliosis. We are continuing our studies on PG of iliac crest cartilage biopsied from children with skeletal growth disorders such as pseudoachondroplasia, achondroplasia, and various forms of spondyloepiphyseal dysplasias and try to correlate the biochemical data with clinical, histological and electron microscopic abnormalities.